She-bolt type gripper device for a concrete wall form tie rod

ABSTRACT

A releasable, reusable, slip-on, she-bolt type gripper device designed for telescopic reception therein of one end of a cylindrical horizontally extending tie rod for use in connection with a concrete wall form in the form of a pair of spaced apart, upstanding sides and adapted to receive the reaction pull of the tie rod when the latter is under tension as the result of pouring of wet concrete between the sides of the form. Longitudinally shiftable, chuck-forming jaw segments within a tapered casing or shell are spring-biased so that they frictionally engage the adjacent end of the associated tie rod and are self-energized by the longitudinal pull of the latter. A spring-biased pull rod is connected in common to all of the jaw segments, projects rearwardly through the outer end of the shell and, when pulled rearwardly, releases the jaw segments from the tie rod. When the gripper device projects through the adjacent side of the associated form and into the poured concrete, an elastomeric sealing ring at the forward end of the shell prevents seepage of concrete thereinto. When the gripper device is used with concrete wall forms of the &#39;&#39;&#39;&#39;Steel-Ply&#39;&#39;&#39;&#39; type, it remains exteriorly of the adjacent form side and does not project into the concrete with the result that the sealing ring may be omitted.

United States Patent [191 Connors Oct. 7, 1975 SHE-BOLT TYPE GRIIPERDEVICE FOR A CONCRETE WALL FORM TIE ROD [75] Inventor: Frank T. Connors,Deerfield, Ill.

[73] Assignee: Symons Corporation, Des Plaines,

Ill.

[22] Filed: Nov. 22, 1974 [21] Appl. No.: 526,076

[52] US. Cl. 249/40; 24/136 R; 52/223 L;

249/216; 254/29 A; 425/111 [51] Int. Cl. E04G 11/06; E04G 17/06 [58]Field of Search 249/40, 213, 215, 216,

249/217, 219 R, 219 W, 190, 43, 91, 97; 264/228, 229; 24/136 R; 52/223L; 425/111 Primary Examiner-Francis S. Husar Assistant Examiner-John S.Brown Attorney, Agent, or FirmNorman H. Gerlach [57] ABSTRACT Areleasable, reusable, slip-on, she-bolt type gripper device designed fortelescopic reception therein of one end of a cylindrical horizontallyextending tie rod for use in connection with a concrete wall form in theform of a pair of spaced apart, upstanding sides and adapted to receivethe reaction pull of the tie rod when the latter is under tension as theresult of pouring of wet concrete between the sides of the form.Longitudinally shiftable, chuck-forming jaw segments within a taperedcasing or shell are spring-biased so that they frictionally engage theadjacent end of the associated tie rod and are self-energized by thelongitudinal pull of the latter. A spring-biased pull rod is connectedin common to all of the jaw segments, projects rearwardly through theouter end of the shell and, when pulled rearwardly, releases the jawsegments from the tie rod. When the gripper device projects through theadjacent side of the associated form and into the poured concrete, anelastomeric sealing ring at the forward end of the shell preventsseepage of concrete thereinto. When the gripper device is used withconcrete wall forms of the Steel- Ply type, it remains exteriorly of theadjacent form side and does not project into the concrete with theresult that the sealing ring may be omitted.

16 Claims, 7 Drawing Figures US. Patent Oct. 7,1975 Sheet 10f3 3,910,546

I m F FIG. 2

76 m mm U.S. Patent Oct. 7,1975 Sheet 2 of3 3,910,546

The improved, releasable, reusable gripper device comprising the presentinvention is designed primarily for use as a slip-on she-bolt for use inconnection with a concrete wall or other form where it is telescopicallyreceived over one end of a horizontally extending tie rod duringconcrete-pouring operations. The invention is, however, capable of otheruses and a gripper device embodying the principles thereof may ifdesired be employed either with or without modification as desired forother uses, as, for example, a dead-end anchor device for a tensionedrod-like member, wire, or the like, or as a pulling device by means ofwhich tension may be applied to a rod or wire. Irrespective, however, ofthe particular use to which the invention may be put, the essentialfeatures thereof remain substantially the same.

A dead-end type anchor or gripper device of the general character underconsideration consists mainly of a tapered tubular casing or shellwithin which there are slidingly disposed a series of contiguous andcircumferentially arranged tooth-equipped jaw segments which form aone-way clutch and grip the rod or wire which is to be held therebetweenwhen tension is applied thereto in one direction. Such an anchor orgripper device is not well adaptable for use as a she-bolt in connectionwith concrete formwork unless it is regarded as being disposableinasmuch as to render it reusable it is necessary to provide a means forreleasing the chuckforming jaw segments which are associated therewith.Furthermore, if such a device projects into the space between the sidesof a concrete form where wet concrete is poured, the problem ofpreventing concrete form seeping into the shell which encloses thechuckforming jaw segments arises.

In the electrical industry, gripper devices of the aforementionedcharacter are made in tandemarranged pairs and are used as permanentwire splices. They also are made as dead-end devices for stranded wireor cable. Certain of these gripper devices are of the type which isreleasable in that when tension in the wire is released, the wire may beshoved rearwardly into the shell of the device in order to release thepressure of the jaw segments, after which a tool may be introducedthrough an opening in the side wall of the shell to hold the segmentsreleased until the wire is drawn from the shell. One particular gripperdevice which is currently on the market employs a slotted shell throughwhich a radially extending segmentmanipulating finger extends so that itis possible collectively to release the jaw segments while the wire isstill under tension. These various gripper devices are not well adaptedfor use as she-bolts in the concrete form industry inasmuch as with theslotted type of shell, it is impossible to release the tension in thetie rod after the concrete has become hardened. Where a radial finger isused for jaw segment release, such finger is not always disposed in aconvenient place where it is readily accessible for manipulation due tothe presence of adjacent obstructions such as waler boards, strongbacks,or nearby concrete form hardware.

The present invention is designed to overcome the above-notedlimitations that are attendant upon the construction and use ofconventional gripper devices of the character under consideration and,toward this end,

the invention contemplates the provision of a gripper device which isparticularly well-adapted for use as a she-bolt in a concrete wall orother form, regardless of whether the latter be comprised of plywoodpanels wherein the device projects through the adjacent side of theconcrete form and into the area where concrete is poured or whether theform be comprised of Steel- Ply form panels of the type which ismanufactured and sold by Symons Corporation of Des Plaines, Ill. In thelatter instance, the gripper device which is employed in connection withthe form must necessarily remain on the outer side of the adjacent formside where it is not exposed to concrete-pouring operations. Theprovision of such a gripper device constitutes the principal object ofthe present invention.

Briefly, in carrying out this object the invention contemplates theprovision of a gripper device which has the usual tapered shell withinternal chuck-forming segments but instead of embodying a radial chuckrelease finger which projects laterally through and from the shell,employs a longitudinally extending pull rod which is coaxial with theshell, is connected in common to the rear ends of the chuck-formingsegments and extends rearwardly of the shell and, therefore, is alsocoaxial with the tie rod which is gripped. The device is thusnecessarily a dead-end gripper device and its use as a wire or rodsplice is not intended. Additionally, in order further to adapt thegripper for use as a she-bolt, the pull rod extends only a slightdistance rearwardly of the chuck-enclosing shell and it is provided onits extreme rear end with an enlarged pry head which may be engaged by asuitable tool such as a carpenters claw ham mer for chuck-releasepurposes. By such an arrangement, when it is desired to dismantle aconcrete form, it is merely necessary to pry the pull rod rearwardly inorder to release the chuck-forming jaw segments from the adjacent end ofthe tie rod, after which the device may be slid bodily as a unit fromthe tie rod and, consequently, from the form where it may be reused inconnection with another concrete form.

A further object of the invention is to provide a shebolt type gripperdevice which is generally of new and improved construction and combineshigh efficiency with cheapness of construction.

Other objects of the invention and the advantages and characteristics ofthe present gripper device will be apparent from a consideration of thefollowing detailed description.

The invention consists in the several novel features which arehereinafter set forth and are more particu larly defined by the claimsat the conclusion hereof.

Two embodiments of the invention are disclosed in the accompanying threesheets of drawings in which:

FIG. 1 is a fragmentary perspective view, partly in section, of aconcrete wall form showing one form of the improved gripper device inuse as a slip-on she-bolt;

FIG. 2 is an enlarged longitudinal sectional view taken on thehorizontal plane indicated by the line 22 of FIG. 1 and in the directionof the arrows;

F IG. 3 is a transverse sectional view taken on the line .33 of FIG. 2;

FIG. 4 is a fragmentary sectional view similar to FIG. 2 and somewhatschematic in it representation, illustrating the manner in which thegripper device is released from the associated tie rod;

FIG. 5 is an enlarged reentrant exploded perspective view of the gripperdevice of FIG. 2 showing all of the constituent parts thereof;

FIG. 6 is a fragmentary perspective view of a concrete wall formembodying wooden strongbacks and walers and showing a modified form ofthe gripper device employed as a she-bolt where it projects completelythrough the adjacent form side and into the poured concrete; and

FIG. 7 is an enlarged longitudinal sectional view taken on thehorizontal plane indicated by the line 7-7 of FIG. 6 and in thedirection of the arrows.

Referring now to the drawings in detail and in particular to FIGS. 1 and2, a fragmentary portion of a concrete wall form of conventionalconstruction is illustrated therein and designated in its entirety bythe reference numeral 10. The wall form 10 is made up of two upstanding,spaced apart series 12 and 14 of rectangular panel units 16, the unitsof each series being arranged in edge-to-edgc relationship and formingone side of the wall form. The panel units 16 of the two series aremaintained in spaced parallel relationship by means of combined spreaderand tie rod assemblies 18, two such assembliesbeing illustrated in FIG.1 as being associated with two adjacent panel units of each of the twoseries 12 and 14 in the production of a concrete wall 20 (see FIG. 2),such wall being omitted in FIG. 1 in the interest of clarity.

The individual panel units 16 which are illustrated in FIGS. 1 and 2 arein the form of conventional prefabricated Steel-Ply panels and no claimis made herein to any novelty associated with the same. The novelty ofthe present invention resides rather in the construction and design ofthe tie rod assemblies 18, and particularly in the construction of thespecific gripper devices which form a part thereof. The nature andfunction of such gripper device will be described in detail presently,these gripper devices functioning in the manner of she-bolts formaintaining tension in the tie rods of the assemblies 18 when wetconcrete is poured between the sides of the wall form 10, and beingdesignated in their entirety by the reference numeral 22. Theillustrated panel units 16 consist of rectangular plywood facings 24 andsteel marginal rectangular reinforcing frames on the outer faces of thefacings. As shown best in FIG. 1, the reinforcing frames of the panelsl6 consist of vertical and horizontal frame mem bers, only the verticalframe members 26 being illustrated in the drawings. At appropriatelevels in the form, suitable horizontal struts or crossbars 28 of angular construction extend across the panel units between the opposedvertical frame members 26. Specifically, the vertical frame members ofthe reinforcing frames are in the form of structural steel members whichare generally of shallow U-shape cross section and comprise spacedmarginal parallel ribs 30 and 32 and a connecting base portion or web 34between the ribs. On the sides of the web 34 which are opposite the ribs30 and 32 there are formed shallow longitudinally extending ribs'36which define angular grooves or recesses 38 for reception therein of theextreme vertical edge regions of the plywood fac'ings 24. The horizontalcrossbars 28 are welded to the inside faces of the vertical framemembers 26. At vertically spaced regions along the vertical framemembers 26, the ribs 30 and 32'are notched as at 40 .to accommodate thetie rod assemblies 18, while the web portions 34 of the bars 26 areformed with rectangular openings 42 in horizontal register with thenotches 40 for reception therethrough of conventional connecting boltand wedge assemblies 44 by means of which adjacent panel units arefastened together, all in a manner that will be made clear presently.

Still referring to FIGS. 1 and 2 of the drawings, each combined spreaderand tie rod assembly 18 is comprised of a horizontally extending tie rodand a pair of the aforementioned novel gripper device 22 which in theillustrated environment and as previously stated function in the mannerof she-bolts for assimilating the tension in the tie rod 50 at such timeas wet concrete is poured between the two sides of the form 10. Atregions spaced inwardly from the ends of each tie rod 50 and slightlywithin the confines of the concrete form, the tie rod is provided withthe usual weakened portions or breakbacks 51, thus dividing the tie rodinto a medial portion 52 which remains embedded within the hardenedconcrete wall 20, and end portions 53 which normally project through thevoids which are defined by the aforementioned registering notches 40 inthe adjacent vertical frame members 26 and receive thereover the gripperdevices 22.

Still referring to FIGS. 1 and 2, and additionally to FIGS. 3, 4 and 5,each gripper device 22 of each combined spreader and tie rod assembly 18involves in its general organization an elongated tubular metal shell 54having a rear cylindrical section 55 and a forward frusto-conicalsection 56, the shell being open-ended. Disposed within the forwardfrusto-conical section 56 is a chuck comprising a series of four jawsegments 58, each of which is of elongated tapered design as best shownin FIG. 5. Each jaw segment is provided with a curved outer surface 60(see FIG. 3) which is adapted to slide longitudinally on the innersurface of the forward frusto-conical section 56 of the shell 54, and inaddition a curved inner tie rod-gripping surface which is in the form ofa longitudinal series of teeth 62, the latter extending along a majorportion of the length of the segment. Except for the curvature of theaforementioned outer and inner surfaces, each jaw segment is generallytrapezoidal in transverse cross section. The various jaw segments 58 areadapted to encompass the adjacent end of the tie rod 50 when the shell54 is telescopically projected thereover as best illustrated in FIG. 2.

As clearly shown in FIG. 5 of the drawings, the rear end region of eachjaw segment 58 is recessed as indicated at 64 so as to providea web 66and a hook-like head portion 68 which, in effect, constitutes alongitudinally and rearwardly displaced extension of the main bodyportion of the segment. In the assembled position of the jaw segmentsabout the adjacent projecting end of region 53 of the associated tie rod50, the various re-. cesses 64 define a complementary sectional void forreception therein of a disk-like pull flange 70 which is in the form ofa Maltese Cross and has extending therethrough a central opening 72. Inthe peripheral portion of the pull flange 70, there are formed fourequidistantly spaced radially and inwardly extending notches 73 andthese are adapted to receive and interlock with the webs 66 at the rearend regions of the jaw segments 58 to the end that the pull flange is insuch fixed interconnected relation with the jaw segments as to causeaxial displacement of the segments when the pull flange is pulledrearwards, while at the same time permitting the segments to moveradially within the forward frusto-conical section 56 of the shell 54.The forward end region of a pull rod 74 extends through the opening 72.Said pull rod is disposed in coaxial relation with the shell 54 andembodies on its forward end a fixed enlargement 76 which, as shown inFIGS. 2 and 4 abuts against the front end face of the pull flange 70.The medial region of the pull rod 74 extends slidably through a circularopening or hole 78 in the central portion of a circular rear end wall 80of the shell 54. The rear rim 82 of the rear cylindrical section 55 ofthe shell 54 is beaded over the periphery of the end wall 80 in orderfixedly to hold the latter in place, while the rear end of the pull rod74 is provided with a fixed cap 84 which may be threaded thereon orotherwise fixedly secured thereto. A helical compression spring 86 isdisposed within the shell 54 and encompasses the medial region of thepull rod 74. The rear end of the spring 86 bears against the end wall 80and the front end of the spring abuts against the rear end faces of thehook-like head portions 68 of the segments 58. When the jaw segments 58are pulled rearwards by exerting a pulling force either manually or byway of a tool on the cap 84 at the rear end of the pull rod, they arepermitted to move ra dially outwards into an expanded position whereinthey are released from gripping relation with the adjacent end region ofthe tie rod 50. However, when no rearward force is exerted on the pullrod, the helical compression spring 68 serves to urge the jaw segmentsforwards to the end that they are contracted by the camming action ofthe forward frusto-conical section of the shell into firm grippingrelation with the adjacent end region of the tie rod.

In the installation of the herein described gripper device 22 over theadjacent outwardly projecting end portion 53 of the tie rod 50, abottomless seating cup 90 is positioned against the outer side faces ofthe adjacent pair of adjacent vertical frame members 26. Such seat ingcup is provided therein with a frusto-conical seating socket 92 for theextreme forward end region of the forward frustoconical section of thegripper shell 54 as clearly shown in FIGS. 1 and 2. If desired, suchseating cup may be permanently connected to the forward end of theshell.

It will be observed that in its normal state, the spring 86 within theshell 54 yielding urges the four chuck segments 58 forwardly so thatthejaw teeth 62 of such segments tend to close upon one another.However, at such time as the shell 54 is inserted into the seating cup90 as previously described, the extremity of the adjacent end portion 53of the tie rod 50 forces the jaw segments rearwardly against the actionof the spring 86, thus spreading the segments apart so that such endportion 53 may enter between the segments and become gripped thereby atsuch time as forward pressure on the device 22 is terminated. With thetie rod 50 thus gripped, the gripper device 22 functions as a she-boltfor the assembly 18 of which it forms a part.

When concrete form dismantling operations are resorted to, each ofthevarious gripper devices 22 may be withdrawn from its associated tie rodend region 53 by the simple expedient of utilizing a suitable tool suchas a pry bar or a claw hammer such as is illustrated in dotted lines inFIG. 4 against the cap 84 which, in effect, constitutes a pry head, thusdrawing the pull rod 74 rearwardly and, as a consequence, pulling thefour check segments 58 rearwardly so as to release their jaw pressure onthe adjacent tie rod end region 53. The gripper device 22 may then beremoved from the tie rod and reserved for reuse in a subsequent concreteform installation.

In FIGS. 6 and 7 of the drawings, a slightly modified form of gripperdevice 122 is disclosed, such device being suitable for use with an allwood concrete wall form such as is disclosed in these views. Theillustrated form embodies plywood panels 124 which are backed byhorizontal waler boards 123 and vertical strongbacks 125 conventionallyarranged to produce the opposing form sides 112 and 114. Due to thesimilarity between the previously described gripper device 22 of FIGS. 1to 5, inclusive, and the modified form of gripper device of FIGS. 6 and7, and in order to avoid needless repetition of description, similarreference numerals but of a higher order have been applied to the conesponding parts as between the disclosure of FIGS. 6 and 7 on the onehand and FIGS. 1 to 5 on the other.

The shell 154, chuck segments 158, pull rod 174 and spring 186 of thegripper device 122 remain substantially the same as the correspondingparts of the gripper device 22 with the sole exception that inasmuch asthe forward end of the shell of the gripper device 154 projects throughan opening 127 in the associated plywood panel 124, it is necessary toseal such forward end of the shell against the entrance of wet pouredconcrete. Accordingly, the forward frusto-conical section 156 of theshell 154 has its forward end cupped inwardly as indicated at 157 so as,in effect, to define an annular front wall for the shell. Seated withinsuch cupped portion and forwardly of thefour chuck segments 158 there isdisposed a doughnut-like sealing ring 159 of any suitable elastomericmaterial. Otherwise, the gripper device 122 remains substantially thesame as the gripper device 22, both as regards its structure and itsfunction.

In the installation of the gripper device 122 in a wall form such as theillustrated form 110, the device projects between the verticallydisposed strongbacks 125 and beneath the waler 123 exteriorly of theplywood panel 124. In order to accommodate the gripper device 122, thehole 127 is formed in the plywood panel for projection therethrough ofthe forward tapered or frusto-conical section 156 of the shell 154.

In this second or modified form of the invention, since the forward endof the shell 154 projects through the plywood facing 124 and into theconcrete, the seating cup 90 which is associated with the previouslydescribed first form of the invention is omitted and, in its place,there is provided a seating plate of rectangular configuration, theplate being formed with a central circular opening 129 therein throughwhich extends the rear end region of the rear cylindrical section of thegripper shell 154. The beaded rim 182 of the shell 154 bears againstthis seating plate 190 as clearly shown in FIG. 7 and thus assimilatesthe tension in the associated tie rod assembly 118.

In connection with either concrete form 10 or 1 10 as illustrated in theaccompanying drawings, after the as sociated gripper device has beenwithdrawn from the adjacent projecting end region of the associated tierod, it will be understood that said projecting end region will bewrested from the hardened concrete in a manner well-known in the art.

The invention is not to be limited to the exact ar rangement of partsshown in the accompanying drawings or described in this specification asvarious changes in the details of construction may be resorted towithout departing from the spirit or scope of the in vention. Therefore,only insofar as the invention is particularly pointed out in theaccompanying claims is the same to be limited.

I claim:

1. A gripper device adapted for application to one end of a cylindricalrod and comprising an open-ended, tapered, tubular shell having a smallfront end and a large rear end, a plurality of correspondingly tapered,tooth-equipped jaw segments slidably disposed within said shell incircumferentially arranged relationship and defining a chuck structurefor reception ofsaid one end of the rod when it is projected into thefront end of-the shell, a wall extending across the rear end of saidshell, a compression spring disposed between said wall and jaw segmentsand effective to bias the latter forwardly in the shell, and a pull rodprojecting centrally through said wall coaxially with the shell andhaving its forward end operatively connected in common to the rear endsof said jaw segments and effective when pulled rearwardly to releasesaid segments from the rod.

2. A gripper device as set forth in claim 1 and wherein each of said jawsegments is formed with a hook-like head portion at its rear end, andthe forward end of the pull rod carries a pull flange havinginterlocking engagement with said head portions.

3. A gripper device as set forth in claim 1 and wherein the rear endregion of each jaw segment is recessed to provide a rearwardly displacedhooklike head portion which is connected to the main body of the segmentby a web, and a pull flange is carried on the forward end of the pullrod and projects into the recessed portions of the chuck segments.

4. A gripper device as set forth in claim 3 and wherein said pull flangeis in the form of a Maltese Cross which substantially fills the recessedportions of the jaw segments.

5. A gripper device as set forth in claim 4 and wherein said pull flangeis slidable on the pull rod and the forward end of the latter isprovided with an enlargement by means of which rearward pull of the pullrod is transmitted to the pull flange.

6. A gripper device as set forth in claim 5 and wherein said pull rodprojects rearwardly of the wall a slight distance and is provided withan enlarged pry head which is designed for engagement by a pry tool forforcing the pull rod rearwardly.

7. A gripper device designed for use as a she-bolt in gripping theprojecting end of a concrete-embedded tie rod in associated relationwith a concrete wall form, said device comprising a tapered tubularshell of circular cross section and with a small front'end and a largerear end, a plurality of correspondingly tapered, toothed-equipped jawsegments slidably disposed within said shell in circumferentiallyarranged relationshipand defining a chuck structure for reception ofsaid tie rod end, a rear circular wall extending across and fixedlyconnected to the rear end of said shell, a

compression spring interposed between said wall and said chuck segmentsand said front annular wall, and a pull rod projecting centrally throughsaid rear annular wall coaxially with the shell, having its forward endoperatively connected in common to the rear ends of said chuck segments,and effective when pulled rearwardly to release said segments from thetie rod.

8. A gripper device as set forth in claim 7 and wherein the forward endof said shell is cupped inwardly to provide said front annular wall.

9. A gripper device as set forth in claim 8 and wherein each of said jawsegments is formed with a hook-like head portion at its rear end, andthe forward end of the pull rod carries a pull flange havinginterlocking engagement with said head portions.

10. A gripper device as set forth in claim 7 and wherein the rear endregion of each jaw segment is recessed to provide a rearwardly displacedhook-like head portion which is connected to the main body of thesegment by a web, and a pull flange is carried on the forward end of thepull rod and projects into the recessed portions of the chuck segments.

11. A gripper device as set forth in claim 10 and wherein said pullflange is in the form of a Maltese Cross which substantially fills therecessed portions of the jaw segments.

12. A gripper device as set forth in claim 11 and wherein said pull rodprojects rearwardly of the rear circular wall a slight distance and isprovided with an enlarged pry head designed for engagement by a pry toolfor forcing the pull rod rearwardly.

13. In a concrete wall form, in combination, a pair of upstanding wallform sides between which wet concrete is adapted to be poured in theformation of a concrete wall, each of said sides embodying edge-to-edgerectangular panels in the form of plywood facings and rectangularmetallic reinforcing frames around the facings, a combined tie rod andspreader assembly for maintaining said form sides in their spaced apartrelationship,

said tie rod and spreader assembly embodying a horizontal tie rod havinga medial portion designed for embedment in the concrete which is pouredbetween said form sides, and projecting end portions which extendbetween and beyond the abutting side members of the reinforcing framesof the panels, and a pair of gripper devices disposed in grippingrelationship with respect to said projecting end portions of the tierod, each gripper device comprising a tapered tubular shell embodying asmall front end and a large rear end, a plurality of correspondinglytapered, toothed-equipped jaw segments slidably disposed within saidshell in circumferentially-arranged relationship and defining a chuckstructure which receives the adjacent projecting end portion of the tierod, a compression spring disposed in the shell and effective to biasthe jaw segments forwardly in the shell, and means for effecting releaseof said sections from the adjacent projecting end portion of the tie rodwhen it is desired to remove the gripper device from said projecting endportion of the tie rod, and a pair of bottomless seating cups positionedagainst the outer faces of the abutting side members of the re inforcingframes, surrounding said projecting end regions of the tie rod, andhaving the small ends of the shells of the gripper devices fittingsnugly therein.

14. In a concrete wall form, the combination set forth in claim 13 andwherein said bottomless seating cups are permanently attached to thesmall ends of the shells of the gripper devices.

15. In a concrete wall form, in combination, a pair of upstanding wallform sides between which wet concrete is adapted to be poured incidentto the creation of a concrete wall, each of said sides embodying anupstanding plywood panel together with outer wooden reinforcing members,and a combined tie rod and spreader assembly for maintaining said formsides in their spaced apart relationship, said tie rod and spreaderassembly embodying a tie rod having a medial portion designed forembedment in the concrete which is poured between said form sides, andprojecting end portions which extend through openings in the respectiveplywood panels, and a pair of gripper devices disposed in grippingrelationship with respect to said projecting end portions of the tierod, each gripper device comprising a tapered tubular shell embodying asmall front end and a large rear end and having its front end projectingthrough the tie rod-receiving opening in the associated plywood panel insealing relationship, a plurality of tapered, toothed-equipped, jawsegments slidably disposed within said shell in circumferentially arranged relationship and defining a chuck structure which receives theadjacent projecting end portion of the tie rod, a rear wall extendingacross the rear end of said shell, a compression spring disposed in theshell and interposed between said wall and jaw segments and effective tobias the latter forwardly in the shell, the forward end of said shellbeing cupped inwardly to provide a front wall for the shell andreceiving said adjacent projecting end portion of the tie rodtherethrough, an elastomeric sealing ring interposed between the forwardends of said jaw segments and said front wall of the shell, and a pullrod projecting centrally through said rear wall coaxially with the shelland having its forward end operatively connected in common to the rearends of said jaw segmentsand effective when pulled rearwardly to releasesaid segments from the adjacent projecting end portion of the tie rod.

16. In a concrete wall form, the combination set forth in claim 15 andwherein said pull rod projects rearwardly of the rear wall a slightdistance, the rear rim of the shell is provided with an external bead,and a seating plate having a central opening therethrough istelescopically received over said shell, bears against woodenreinforcing members, and receives the inward thrust of said externalbead incident to the tension in the tie rod and spreader assembly.

1. A gripper device adapted for application to one end of a cylindricalrod and comprising an open-ended, tapered, tubular shell having a smallfront end and a large rear end, a plurality of correspondingly tapered,tooth-equipped jaw segments slidably disposed within said shell incircumferentially arranged relationship and defining a chuck structurefor reception of said one end of the rod when it is projected into thefront end of the shell, a wall extending across the rear end of saidshell, a compression spring disposed between said wall and jaw segmentsand effective to bias the latter forwardly in the shell, and a pull rodprojecting centrally through said wall coaxially with the shell andhaving its forward end operatively connected in common to the rear endsof said jaw segments And effective when pulled rearwardly to releasesaid segments from the rod.
 2. A gripper device as set forth in claim 1and wherein each of said jaw segments is formed with a hook-like headportion at its rear end, and the forward end of the pull rod carries apull flange having interlocking engagement with said head portions.
 3. Agripper device as set forth in claim 1 and wherein the rear end regionof each jaw segment is recessed to provide a rearwardly displacedhook-like head portion which is connected to the main body of thesegment by a web, and a pull flange is carried on the forward end of thepull rod and projects into the recessed portions of the chuck segments.4. A gripper device as set forth in claim 3 and wherein said pull flangeis in the form of a Maltese Cross which substantially fills the recessedportions of the jaw segments.
 5. A gripper device as set forth in claim4 and wherein said pull flange is slidable on the pull rod and theforward end of the latter is provided with an enlargement by means ofwhich rearward pull of the pull rod is transmitted to the pull flange.6. A gripper device as set forth in claim 5 and wherein said pull rodprojects rearwardly of the wall a slight distance and is provided withan enlarged pry head which is designed for engagement by a pry tool forforcing the pull rod rearwardly.
 7. A gripper device designed for use asa she-bolt in gripping the projecting end of a concrete-embedded tie rodin associated relation with a concrete wall form, said device comprisinga tapered tubular shell of circular cross section and with a small frontend and a large rear end, a plurality of correspondingly tapered,toothed-equipped jaw segments slidably disposed within said shell incircumferentially arranged relationship and defining a chuck structurefor reception of said tie rod end, a rear circular wall extending acrossand fixedly connected to the rear end of said shell, a compressionspring interposed between said wall and jaw segments and effective tobias the latter forwardly in the shell, a front annular wall extendingacross the front end of the shell and through which the projecting endof the tie rod is adapted to extend, an elastomeric sealing ringinterposed between the forward ends of said chuck segments and saidfront annular wall, and a pull rod projecting centrally through saidrear annular wall coaxially with the shell, having its forward endoperatively connected in common to the rear ends of said chuck segments,and effective when pulled rearwardly to release said segments from thetie rod.
 8. A gripper device as set forth in claim 7 and wherein theforward end of said shell is cupped inwardly to provide said frontannular wall.
 9. A gripper device as set forth in claim 8 and whereineach of said jaw segments is formed with a hook-like head portion at itsrear end, and the forward end of the pull rod carries a pull flangehaving interlocking engagement with said head portions.
 10. A gripperdevice as set forth in claim 7 and wherein the rear end region of eachjaw segment is recessed to provide a rearwardly displaced hook-like headportion which is connected to the main body of the segment by a web, anda pull flange is carried on the forward end of the pull rod and projectsinto the recessed portions of the chuck segments.
 11. A gripper deviceas set forth in claim 10 and wherein said pull flange is in the form ofa Maltese Cross which substantially fills the recessed portions of thejaw segments.
 12. A gripper device as set forth in claim 11 and whereinsaid pull rod projects rearwardly of the rear circular wall a slightdistance and is provided with an enlarged pry head designed forengagement by a pry tool for forcing the pull rod rearwardly.
 13. In aconcrete wall form, in combination, a pair of upstanding wall form sidesbetween which wet concrete is adapted to be poured in the formation of aconcrete wall, each of said sides embodying edge-to-edge rectangularpanels in the form of plywood facings and rectangular metallicreinforcing frames around the facings, a combined tie rod and spreaderassembly for maintaining said form sides in their spaced apartrelationship, said tie rod and spreader assembly embodying a horizontaltie rod having a medial portion designed for embedment in the concretewhich is poured between said form sides, and projecting end portionswhich extend between and beyond the abutting side members of thereinforcing frames of the panels, and a pair of gripper devices disposedin gripping relationship with respect to said projecting end portions ofthe tie rod, each gripper device comprising a tapered tubular shellembodying a small front end and a large rear end, a plurality ofcorrespondingly tapered, toothed-equipped jaw segments slidably disposedwithin said shell in circumferentially-arranged relationship anddefining a chuck structure which receives the adjacent projecting endportion of the tie rod, a compression spring disposed in the shell andeffective to bias the jaw segments forwardly in the shell, and means foreffecting release of said sections from the adjacent projecting endportion of the tie rod when it is desired to remove the gripper devicefrom said projecting end portion of the tie rod, and a pair ofbottomless seating cups positioned against the outer faces of theabutting side members of the reinforcing frames, surrounding saidprojecting end regions of the tie rod, and having the small ends of theshells of the gripper devices fitting snugly therein.
 14. In a concretewall form, the combination set forth in claim 13 and wherein saidbottomless seating cups are permanently attached to the small ends ofthe shells of the gripper devices.
 15. In a concrete wall form, incombination, a pair of upstanding wall form sides between which wetconcrete is adapted to be poured incident to the creation of a concretewall, each of said sides embodying an upstanding plywood panel togetherwith outer wooden reinforcing members, and a combined tie rod andspreader assembly for maintaining said form sides in their spaced apartrelationship, said tie rod and spreader assembly embodying a tie rodhaving a medial portion designed for embedment in the concrete which ispoured between said form sides, and projecting end portions which extendthrough openings in the respective plywood panels, and a pair of gripperdevices disposed in gripping relationship with respect to saidprojecting end portions of the tie rod, each gripper device comprising atapered tubular shell embodying a small front end and a large rear endand having its front end projecting through the tie rod-receivingopening in the associated plywood panel in sealing relationship, aplurality of tapered, toothed-equipped, jaw segments slidably disposedwithin said shell in circumferentially arranged relationship anddefining a chuck structure which receives the adjacent projecting endportion of the tie rod, a rear wall extending across the rear end ofsaid shell, a compression spring disposed in the shell and interposedbetween said wall and jaw segments and effective to bias the latterforwardly in the shell, the forward end of said shell being cuppedinwardly to provide a front wall for the shell and receiving saidadjacent projecting end portion of the tie rod therethrough, anelastomeric sealing ring interposed between the forward ends of said jawsegments and said front wall of the shell, and a pull rod projectingcentrally through said rear wall coaxially with the shell and having itsforward end operatively connected in common to the rear ends of said jawsegments and effective when pulled rearwardly to release said segmentsfrom the adjacent projecting end portion of the tie rod.
 16. In aconcrete wall form, the combination set forth in claim 15 and whereinsaid pull rod projects rearwardly of the rear wall a slight distance,the rear rim of the shell is provided with an external bead, and aseating plate having a central opening thereThrough is telescopicallyreceived over said shell, bears against wooden reinforcing members, andreceives the inward thrust of said external bead incident to the tensionin the tie rod and spreader assembly.